Topological Analysis of the Brainstem of the Australian Lungfish < b > < i > Neoceratodus forsteri < /i > < /b >

This study is intended to serve a double purpose. First it concludes and completes a series of publications on the structure of the brainstem in representative species of all groups of anamniote vertebrates. Within the framework of this comparative program the cell masses in the brainstem and their positional relations are analyzed in the light of the Herrick-Johnston concept, according to which the brainstem nuclei are arranged in four longitudinal, functional zones or columns, the boundaries of which are marked by ventricular sulci. The procedure employed in this analysis essentially involves two steps: first, the cell masses and large individual cells are projected upon the ventricular surface, and next, the ventricular surface is flattened out, that is, subjected to a one-to-one continuous topological transformation [J Comp Neurol. 1974;156:255 –267]. The second purpose of the present paper is to complement our mapping of the longitudinal zonal arrangement of the cell masses in the brainstem ofNeoceratoduswith a subdivision in transversely oriented neural segments. Five longitudinal rhombencephalic sulci – the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, the sulcus intermedius dorsalis and the sulcus medianus superior – and four longitudinal mesencephalic sulci – the sulcus tegmentalis medialis, the sulcus tegmentalis lateralis, the sulcus subtectalis and th e sulcus lateralis mesencephali – could be distinguished. Two oblique...
Source: Brain, Behavior and Evolution - Category: Neurology Source Type: research